When using a roller cam, you must also use a bronze-type distributor/cam gear on the oil pump driveshaft. We used the Milodon (left, PN 21525) oil pump drive assembly. The Lunati (center, PN 88426) bronze gear could have been pressed on and pinned to the original shaft by a local machine shop. The gear (right) has over 8,000 miles on it. Inspect the bronze gear for wear every few thousand miles.